Electromagnetic piston pump



1954 H, w. STRONG ETAL 2,686,280 ELECTROMAGNETIC PISTON PUMP Filed Oct.25, 1949 3 Sheets-Sheet 1 INVENTORS WILLIAM CTRETH EWEY, JOHN B KLINGELAND BYHERBERT W. STRONG.

Aug. 10, 1954 w. STRONG ETAL 2,686,280

ELECTROMAGNETIC PISTON PUMP Filed Oct. 25, 1949 3 Sheets-Sheet 2INVENTORS. WILLIAM QTRETH EW EY.

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' a N L NGE o BY HOEHRBER1K w STRONG.

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8" 10, 1954 H. w. STRONG ETAL 2,686,280

ELECTROMAGNETIC PISTON PUMP Filed Oct. 25, 1949 3 Sheets-Sheet 3 23 2122 2 INVENTORS.

WILLIAM CTRETH EWEY,

Patented Aug. 10, 1954 ELECTROMAGNETIC PISTON PUMP Herbert W. Strong,Cleveland Heights, William C. 'lrethewey,

Cleveland,

Garfield Heights, Ohio Application October 25, 1949,'Serial No. 123,416Claims. (01. 318-125) This invention relatesto pumps, and moreparticularly to an electromagnetic piston pump especially adapted forthe circulation of fluids (liquid or gaseous) which are corrosive orotherwise difiicultto handle.

In order to illustrate the principles-and the advantages of theinvention, they may be considered in connection with the problem ofpumping corrosive fluids such as acids and the like, extremely poisonousor highly inflammable fluids, and fluids difiicult to contain, such asheat transfer liquids.

.By the nature of these fluids, conventional pumps, either of the pistontype or of the centrifugal type, are unsatisfactory and dangerousbecause the pump chamber must be provided with a gland for a piston rod,drive shaft, .or the like, thus presenting a problem of leakage.Moreover, by the nature of such conventional pumps they are not welladapted to .manufacturefrom chemically inert materials such as glass,rubber, and phenolic condensation products.

The most nearly satisfactory pumps for such conditions have heretoforebeen of the diaphragm type. These, however, are far from satisfactorybecause of their low capacity relative to the size of the pump and thedanger of failure of the diaphragm in service.

Since the pump of the invention requires no external motor and .mayeasily be made of waterproof construction, it is also suited for sumpinstallations where the pump is submerged.

This invention provides a solution to the problems outlined abovebyproviding a pump in which there are no parts which flex duringoperation, in which the parts exposed to the fluid may be of material ofany desired chemical characteristics for resistance to corrosion, and inwhich no moving part enters or leaves the confined fluid. Morespecifically, the invention involves a pump in which a floating pistonis reciprocated electromagnetically. The invention .also involves novelelectrical systems by which the movement of the piston is effected.

In its preferred form, .the invention embodies but one moving part,other than the valves, which may be simple check Or flapper valves suchas have previously been employed and present no problem. This movingpart is a piston freely reciprocating in a pump cylinder,electromagnetically coupled with solenoids disposed around the cylinderenergized so as to reciprocate the piston, which constitutes an armaturefor the solenoids. The solenoids are coupled to a power circuit foralternate energization, .the power circuit being controlled by meanssensitive to the position of and John B. Klingel,

the piston so that as it reaches each end of its stroke the appropriatesolenoid is energized to draw it to the other end of the stroke. Thissensitive means is preferably a coil at each end of the cylinder whichis inductively coupled to the driving coils by the piston, thusproviding energy, which, through an appropriate relay system, controlsthe flow of power to the motor coils. The pump of the invention is insome respectssimilar to those disclosed in Van Depoele Patents 458,473and 461,295, but differs greatly therefrom in the means for energizingthe solenoids and in adaptability to corrosive fluids.

The nature of the invention and the objects and advantages thereof maybe more clearly understood by reference to the following description ofthe preferred embodiment thereof, and to the drawings in which Fig. 1 isa. longitudinal section of a pump in accordance with the invention; Fig.2 is a diagram of one form of relay or control circuit for the ump; andFig. 3 is .a diagram of a second form of control circuit.

The preferred form of pump, illustrated in Fig. 1, comprises acylindrical body I! of plastic formed with a central bore or cylinder l2 within which a piston or plunger 13 reciprocates freely. The piston isformed of a bundle of soft iron wires 14 imbedded in and coated over theentire exterior surface by a plastic material [5. This material may bepoured over a bundle of the wires in a fluid condition, thus filling theinterstices between the wires serving as a binder. The plastic materialalso covers the entire outer surfaces of the piston, which result may beobtained by pouring the material into a mold which is removed after ithas solidified, or by spraying the outer surface of the piston. Thepiston thereafter may be turned or otherwise finished. Magnetic materialin other forms than wire may be used. Preferably, the diameter of thewires is less than that shown in the drawings, the size beingexaggerated for clarity of the drawings. The circumferential layer ofnon-magnetic material should be as thin as practicable to reduce the airgap between the iron core and the propelling or motor coils. These coils2i and 22 are enclosed within the plastic body I l which body comprisesa cylinder wall it. The body also encloses pick-up or control coils 23and 2% adjacent the end thereof. As will be noted, all the coils areconcentric with the cylinder. They may be preformed and then impregnatedwith the plastic in this condition, or, if desired, the coils may bewound in place and the outer shell I], which encloses thecoils and isdesirable from the standpoint of protection of the coils may be added,or other assembly methods may be used. The plastic body and plasticshell for the piston are desirable for elimination of exposed metallicparts which would be harmed by the fluid acted upon by the pump;however, it will be apparent that from the structura1 standpoint othermaterials could be used. The cylinder wall It should be of anon-magnetic material and one not subject to corrosion by the fluid. Theremainder of the body 2!, if protected from the fluid, may be of amaterial which is not corrosionresistant.

Annular disks 23 of magnetic material serve to shield the control coilsfrom the adjacent motor coils and thus prevent excessive couplingbetween these coils when the piston is not within the control coils.

It will be noted the piston 13 is of somewhat greater length axially ofthe cylinder than the.

motor coils 2i and 22, and, if either coil is energized, it will exert aforce on the piston tending to center it in the field of force of thecoil and thus pull it toward the end of the cylinder. Thus, if the coils2i and 22 are energized alternatively, the piston will be reciprocated.

The pump also comprises suitable valves of the check valve type tocontrol fluid flow into and out of the chambers H9 at each end of thecylinder. These valves are shown schematically, since the invention doesnot depend upon the specific type or location of these valves. Asillustrated, the pump comprises an intake 50 which divides into branches5! and 52 coupled to intake valves 53 and 54. These valves are coupledto conduits 55 and 56, respectively, provided with branches 51 and 58for connection to the chambers I9. The conduits 5t and 51 alsocommunicate with outlet valves 59 and 60 which discharge throughconduits 6! and 62 into the pump outlet 64.

Suitable means must be provided to couple the conduits 51 and 58 to thepump, and the preferred arrangement comprises flanges 63 secured to theends of the body by cap screws 61 and constituting heads for thecylinder. The flanges are provided with openings 68 within which aconduit may be secured in any appropriate manner; A gasket 10 isprovided between each flange and the body and may extend within thecylinder so as to provide a buffer for the piston. The flanges 68 may bethreaded or otherwise adapted for securing the conduits 51 and 58 to theflanges.

It will be apparent that the valves and conduits coupling them to thecylinder and to the inlet and outlet could be within the body of thepump, but the specific arrangement is not regarded as material to theinvention, and it is preferable in some respects to mount the valvesoutside the coil housing or body I I.

It will be noted that each end of the cylinder with its valvesconstitutes a complete pump, and could operate alone. The double-endedarrangement is preferable, however, in that it eliminates the necessityfor piston rings or packing and eliminates leakage, balances the load onthe two piston strokes, and provides greater capacity for agiven size ofpump at a given speed of operation.

A preferred form of control for the pump of the invention is illustratedin Fig. 2, in which the motor coils 2! and 22 and the control coils 23and 24 are illustrated in aligned relation as in the pump. One line 25of an A. C. power source is connected to a common junction of the twomotor coils and the other line 26 of the A. C.

power source is connected through ignitron tubes 21 in back-to-backconnection to a line 3| leading to the motor coil 2|. The A. C. line 26is also coupled through ignitron tubes 28 to energize the line 32leading to the motor coil 22. The line 26 is connected to the cathode 33of one ignitron tube of each set, and to the anode or plate 34 of theother tube of the set, lines 3| and 32 being likewise connected to oneanode and one cathode. The igniter 35 of each tube is con.- nected tothe cathode through an individual secondary winding 35 of a saturabletransformer 31 controlling tubes 21, or 33 controlling tubes 23. Thetransformers 31 and 38 include primary windings 29 connected in parallelto the A. C. power line. These transformers are of a wellknown type inwhich the transformer core may be saturated by passing direct currentthrough a winding of the transformer, and, when the winding is thussaturated, the transformer action is reduced from its normal value to arelatively small fraction thereof. When the transformers are notsaturated, the voltage induced in the windings 3c is sufficient toignite the tubes 21 and 28, each tube thus conducting current during onehalf-cycle of the alternating current so that the motor coil 2! iscontinuously energized when the transformer 31 is unsaturated and themotor coil 22, likewise, when the transformer 38 is unsaturated. Thesaturating winding 39 of the transformer 31 may be energized by thecurrent induced in the control coil 23, which is coupled to thesaturating winding 29 through a fullwave rectifier M of the dry disktype or any other suitable rectifier. The saturating winding 40 in thetransformer 38 is similarly energized by the pick-up coil 24 through therectifier 42. The saturating coil 40 may also be energized from asecondary winding 43 of the transformer 31 through a full-wave rectifierand the saturating winding 39 from a secondary winding 44 of thetransformer 38 through a rectifier 46.

The operation of this system may be described, assuming that the motorcoil 2! is energized and is drawing the piston into the coil 23. Voltageinduced by transformer action between the coils 2! and 23 passes throughthe rectifier 4|, energizing the saturating coil 39. The saturation ofthe core of the transformer 31 greatly reduces the voltage of the coil36 so that the tubes 21 and 29 will no longer fire and cease to conductcurrent at the end of the half cycle, thus deenergizing the coil 2|.

While the transformer 31 is unsaturated, the saturating winding 40 ofthe opposing transformer is energized by the winding 43 through therectifier 45, and thus tubes 28 are non-conducting and motor coil 22deenergized. The saturation of the transformer 31 substantiallydeenergizes the coil 43, increasing the voltage on the igniters of tubes28 and energizing the coil 22. The piston I3 is thus pulled to the rightto ward the center of the coil 22 and couples it electromagneticallywith the coil 24. E. M. F. induced in coil 24 rectified at 42 energizesthe winding 40 and saturates the transformer 38, thereby rendering thetubes 28 non-conducting and deenergizing coil 22. It also deenergizeswinding 44, and the transformer 31 is no longer saturated by this coil.The coil 2! then becomes energized, and the piston is shuttled to theleft, completing the cycle.

The form of control just described is believed to be highly suitable,but it will be apparent to ho e Skilled in the art that many other formsof control having the same general characteristics may be employed insubstitution to that described.

Fig. 3 illustrates a control system in which electron-is circuits areeliminated, the relay function being performed by saturable transformersand saturable reactors. in Figs. 2 and 3 are assigned the same referencenumbers. saturable transformers I31 and I38 are similar to those of Fig.2 except that a single output winding I36 is present instead of the twooutput windings 36 of the transformers of Fig. -2.

The transformers I31 and I38 are saturated by coils 3'9 and 40 energizedfrom the control coils through rectifiers H and '42, and each transformer has a secondary winding 43 or 44 which energizes a saturatingwinding of the other transformer through a rectifier 45 or 46, aspreviously described. The A. C. line 25 is connected to both motor coilsas before. The control of power between the line 28 and the lines 3| and32 leading to the individual motor coils is effected in this instance bysaturable reactors instead of ignitrons. The saturable reactor 8| isprovided with a coil 83 in series with the motor coil 2I and thesaturable reactor 82 is provided with a coil 84 in series with the motorcoil 22. The saturating windings 85 and 86 of the reactors BI and 82 areenergized by the secondary windings I36 of the saturable transformersI31 and I38, respectively.

saturable reactors of the type employed in this circuit are well known.When no current flows in the saturating winding 85 or 86, the reactoracts as a simple reactive impedance or choke, offering a relatively highresistance to passage of alternating current through the winding 83 or84. By energizing the saturating winding, the core may be substantiallysaturated so that the impedance of the winding 83 or 84 is greatlyreduced.

In view of the previous extended description of the operation of thecircuit of Fig. 2, it is believed that no such extended description willbe necessary for Fig. 3. In the device of Fig. 2, when the secondarywindings 36 are energized the ignitrons coupled to them conduct current.Under the same conditions of non-saturation of the transformers I31 andI38, current induced in the windings I36 saturates the reactor 8| or 82,

thus, permitting an increase in current of the motor coil from aninsignificant value to full energization. The parallel between theoperation of the two circuits is so clear that further description isbelieved unnecessary.

It will be noted that reactors 8i and 82 are illustrated as saturated byalternating current. Reactors so saturable are available and may be usedwhere the use of alternating current for saturation is desired. It willbe apparent that the output of coils I36 could be rectified if it weredesired to use reactors saturated by direct current.

It is also possible to control the pump by an electromagnetic relaysystem, but we believe that make-and-break contact devices are notcapable of fully satisfactory operation.

We believe it preferable to control the power system by a device such ascoils 23 and 24 or other means responsive to the piston at each end ofthe cylinder. It will be apparent, however, that control may be effectedby a single responsive device at one end of the cylinder. For example,in Fig. 2, coil 24 and rectifier 42 could be omitted. Excitation of coil23 would deenergize coil 40 and Parts which are the same energize coil22 as described above. This would withdraw the piston from coil 23,deenergizing coil 39 and. energizing coil 40. Coil 22 would bedeenergized and coil 2| would be energized, effecting the return strokeand completing the cycle.

We claim:

1. In a pump, a cylinder, two motor solenoids spaced longitudinally ofthe cylinder, a magnetic free piston reciprocable in the cylinderconstituting an armature for and coupled with both solenoids, and meansresponsive to movement of the piston to either end of the cylinder forenergizing the more remote solenoid more strong- 1y than the nearersolenoid to eiTect reciprocation of the piston, the last-named meanscomprising relay means coupled between each solenoid and a source ofpower, a saturable reactor transformer for energizing each relay means,a saturating winding on each transformer, a secondary coil on eachtransformer connected to energize the saturating winding of the othertransformer, a control coil at each end of the cylinder coupled to thesolenoids by the piston when it enters the respective end of thecylinder, and energizing connections from each coil to the saturatingwinding of the transformer controlling the relay means coupled to thenearer solenoid.

2. A system for the electrical control of movement of a membercomprising, in combination. first and second motor solenoids, the saidsolenoids being adapted to be connected to a source of alternatingcurrent, an armature member adapted to be moved with respect to thesolenoids, a control coil positioned adjacent each solenoid and remotefrom the remaining solenoid, the armature including magnetic materialfor increasing the coupling between the motor solenoid and theassociated control coil when the armature is disposed adjacent thesolenoid and one coil, a variable impedance element connected in serieswith each motor solenoid, the impedance element including a voltageresponsive element for varying the impedance of the element, meansconnected between each control coil and the voltage responsive elementsof the variable impedance elements for increasing the impedance of theelement connected in series with the associated motor solenoid and forreducing the impedance of the remaining impedance element uponexcitation of either control coil by increase of coupling with theassociated motor solenoid caused by the armature.

3. A system for the electrical control of movement of a membercomprising, in combination, first and second motor solenoids, the saidsolenoids being adapted to be connected to a source of alternatingcurrent, an armature member adapted to be moved with respect to thesolenoids, a control coil positioned adjacent each solenoid and remotefrom the remaining solenoid, the armature including magnetic materialfor increasing the coupling between the motor sole noid and theassociated control coil when the armature is disposed adjacent thesolenoid and one coil, a variable impedance element connected in serieswith each motor solenoid, the impedance element including a voltageresponsive element for varying the impedance of the element, transformermeans associated with each motor solenoid including a primary windingadapted to be connected to a source of alternating current, a secondarywinding connected to the voltage responsive element of an associatedvariable impedance element connected to the said motor solenoid andadapted to be connected to the source of alternating current, and thirdand fourth windings, and rectifying means connected between the thirdwinding of each transformer and. the fourth winding of the remainingtransformer and rectifying means connected between each control coil andthe fourth winding of the associated transformer for de-energizing eachmotor solenoid and energizing the remaining solenoid upon excitation ofa control coil.

4. The invention in accordance with claim 3, said variable impedanceelement comprising a gaseous conduction device having a controlelectrode as a voltage responsive control element.

5. The invention in accordance with claim 3, 15

said variable impedance element comprising a saturable reactor having asaturating winding as a voltage responsive control element.

References Cited in the file Of this patent UNITED STATES PATENTS NumberName Date 494,956 Johnson, et al Apr. 4, 1893 10 1,647,147 Roller Nov.1, 1927 1,974,262 Cobe Sept. 18, 1934 2,177,795 Von Delden Oct. 31, 19392,182,014 Clark Dec. 5,- 1939 2,443,344

Ekleberry June 15, 1948

